Mold for pneumatic-tire tubes



F. A. SCHWARTZ.

MOLD FOR PNEUMATIC TIRE TUBES. APPLICATION FILED FEB. I0, 1921.

1,388,382. Patented Aug. 23, 1921.

frwezzzar UNITED STATES PATENT OFFICE.

FRED A. SCHWARTZ,'OF BROOKLYN, NEW YORK.

Specification of Letters Patent.

Patented Aug. 23, 1921.

Application filed February 10, 1921. Serial No. 448,917.

To all whom it may concern:

Be it known that I, FRED A. SCHWARTZ, a

citizen of the United States of America, re-

siding in the city of Brooklyn and State of New York, have invented newand useful Improvements in Molds for Pneumatic- Tire Tubes, of which thefollowing specification is an exact and true description, such as willenable others skilled in the" art to which it appertains to make and usethe same.

The invention relates to the construction and vulcanization of casingsthat are usedin combination with pneumatic tubes, the said combinationbeing usually referred to as the pneumatic tire.

The object of the invention is to provide means to correct certainfaulty conditions that obtain with ordinary methods of constructing andvulcanizin casings.

In the process of vu canizing casings 1t has been demonstrated thatbetter results are obtainable when the fabric structure ofthe casing issubjected to pressure that is applied in the direction of the radii ofthe easing simultaneously with ressure that 1mpulses the companion casmgforming mold parts.

To this end various means are being employed, as for example, the casingto be vulcanized is removed from the rigid core upon which it isconstructed and there is substituted an elastic core by which means thecasing is during the process of vulcanization subjected to an expandlngpressure that is admitted to within the elastic core.

With my invention in use, similar results are obtained, and without theexpense of renewing at frequent intervals the elastic cores, and with aconsiderable saving in time and labor consumed in bolting or clampingcompanion casing forming mold parts against the internal pressure.

As will be made plainly evident in this specification, by reason of thenovel conformation of the surface area of the improved core, and groovesof the companion casing formlng mold parts, the fabric or cord structureof the casin during the process of vulcanization, is, by t e use of myinvention subjected to stress that is applied to the fabric or cordstructure in the direction of the plane of the side walls of the casingsimultaneously to the compressing action of the caslng forming moldparts.-

In the accompanying drawin s which.

form a part ofthis specification, lgure l is a cross section of thevulcanized casing in association with a cross section of the improvedequipment; the core and companion casing formmg mold parts whichcomprise the improved equipment being in their relative operativeposition as assumed during the final stage of the process ofvulcanization of the casing.

Fig. 2 is a fragmentary cross section of the vulcanized casing,illustrating by broken lines the conformation as assumed by thesidewalls of the casing when in use.

Flg. 3 is a view similar to Fig. 2, illustrating the method of buildingor mounting the unvulcanized casing upon the core.

The improved equipment may be employed in the construction andvulcanization of casings of the clencher, or straight side type, and thecore forming a part of the improved equipment may be rigid, orcollapsible, and while the equipment is more particularly intended foruse in the construction and vulcanization of casings of the cord plyconstruction, by the use of my improved equipment casings of superiorquality may be produced in the woven fabric ply construction.

The function of the improved equipment is positively reliable, andresults from the novel method of building or mounting the casing uponthe core, and by the conformation given the side walls of the casingduring t e process of vulcanization.

The method of building, or constructing the casing upon the improvedcore is substantially the same as when employing the ordinary equipment;that is the body of the casing consists of several layers, or lies ofrubberized fabric or cord, and upon w ich structure the outer elementsof the casing, as the tread, beads, and side walls of rubber compounds,are secured by vulcanization.

Referring to Fig. 1, and to the core 2, which may be constructed by anypreferred method, as for example it may be cast solid, or hollow, or itmay be constructed of pressed metal parts. It will be noted that thesurface of the core is provided with circumferentially directed grooves,as indiqualities of therubber cement. As will be cated b the numerals 3,3; it will be also results from the closing 'actionof-the mold noted atthese grooves are positioned at parts compressing the several fabricplies substantially the central circumferential line is taken up by thesurface areaof the core between the inner and outer peripheries of thatisp'rovided by the grooves. thecore, and that the conjunction of theThe. vulcanized'casing is removed from concave and convex areas areeffected by the casing forming mold parts and stripped regular, butshorter curved areas, the imfrom the core in the usual manner. Thevulportanoe of WhlOh will be later apparent. canized, but not inflatedcasing" is of the When building the casing upon the im-- sameconformation as the surface area 'of the proved core the surface areafofthe core becasing forming grooves in the companion tween the inner ed es4, 4, of the grooves mold parts in which the casing has been vuland theinwardly directed flan e 5, is given canized, but by reason of thepressure ex he first ply fiferted upon the side walls of the casing by acovering of rubber cement; t of fabric or cord is placed upon the corean the inflated inner air tube, the casing when ,stitched, that is theply is caused to conin service will assume the regular curved form tothe surface area of the core, and the conformation as indicated by thebroken edges are secured to the core by the adhesive lmes 10, 10, Fig.2.

observed by referring to the numerals 7, 7 the side walls of thecasingto the regular Fig. 3, the fabric or cord'structure of cas-'curved surface conformation will effect a ing is not caused to conformto-the'surface compressing pressure in th'e direction of the It may beremarked that the, forcing of area of the grooves; the result is thatwhen plane of the side walls of the casin the,

the casing is finally-completed by the casing result of which willeffect a thickening of builder, there is space between the surface thevrubber compound covering the fabric face of the unvulcanized casing. andreflexing action of the casing when in The operation of the improvedequipuse will be much better withstood b the ment when the casing istobe vulcanized is rubber compound projectin into the abric asfol1ows:'referring to the casing forming structure 0 the casing at t ismost vulnermold parts, and to the annular casin formable point.

ing grooves 8, 8,. Fig. 1, it will be 0 served Having thus described myinvention'withthat the circumferentially'directed'ribs 9, 9, out havingattempted to set forth all'the that are off-set from the inner or moldsidesmodes of its use, I declare that whatI claim of the annular casingforming grooves 8, 8, and desire to secure by Letters Patent is alinewith, and with the casing forming A casing mold comprising aairofcommold parts in closed position engage the p'lementary annularsections eac vhaving an grooves 3, 3, which are circumferentiallydiannular rib offset from its annular concave rected upon the surface ofthe, core. (It, molding surface, and an annular core eleis understoodthat proper clearance is proment having a molding surface normallyexvided for the casing between the ribs and tending between the saidcomplementary grooves when the mold parts are in closed annularsections, the said annular core ele-' position.)

By the means just described, the side walls of the casing are during theprocess of vulcanization caused to conform to the surface area of theannular grooves in the core, and the annular ribs off-set from thecurved surface area of the casing forming grooves. Thus the surplusfabric or cordstock, that ment having grooves opposite the said an nularribs.

In testimony whereof, I afiix my signaarea of the grooves 3,3, and theinner surstructure of the casing. Thus the flexing,

